It appears that a simple mod has made Cortana into a Chinese speaking assistant ahead of Microsoft's official support for the language. Though the procedure allows Cortana to respond in Chinese, you do have to ask your questions in English at this time.
The folks over at Windows Blog Italia managed to show off the Chinese feature in the video below:
It should be noted that Microsoft does not officially support Chinese in Cortana at this time.
Microsoft already promised that Chinese language support will be coming to Cortana soon, so this is promising sign of progress in making Cortana accessible in China.
Thanks, Guy, for the tip.
Source: Windows Blog Italia